It's monitoring app launch and lock screen.
You can unlock app for some minutes or indefinitely.
For privacy or parental control.

For example:
If you lend your phone to children or friends, you can lock all apps except you unlocked.

You can unlock apps by lock screen PIN, pattern or fingerprint.
If your phone is not setup pass code or pattern, app lock does not work.

If you could not unlock apps because you forgot PIN or pattern...
Try phone reboot or safe mode boot(it boots phone with third party app disabled.
* Please use this app at your own risk.

This app uses these permissions only to display ads.
INTERNET
ACCESS_NETWORK_STATE